Earthquakes of magnitude 3.0 or greater occur in Korea about 10 times on average yearly, and the number of earthquakes occurring in Korea is increasing. As many earthquakes have recently occurred, interest in the safety of nuclear power plants has increased. Nuclear power plants are equipped with many cabinet-type control facilities to regulate safety facilities, and function maintenance is required during an earthquake. The seismic performance of the cabinet is divided into structural and functional performances. Structural performance can be secured during the design procedure. Functional performance depends on the vibration performance of the component. Therefore, it is necessary to confirm the seismic performance of the components. Generally, seismic performance is confirmed through seismic simulation tests. When checking seismic performance through seismic simulation tests, it is difficult to determine the effect of frequency and maximum acceleration on an element. In this paper, shaking table tests were performed using various frequencies and various maximum accelerations. The seismic performance characteristics of the functions of electrical equipment components were confirmed through tests.

노후 구조물의 동적 특성 평가를 위해 대표적인 접촉식 센서인 LVDT와 가속도계를 활용한다. 전통 적인 센서의 데이터 신뢰성은 높지만, 작동 원리로 인하여 대상 구조물의 물리적 접근과 센서의 설치 가 필요하다. 조밀한 센서 설치를 위해선 많은 수의 센서와 데이터 수집장치도 추가적으로 필요하다. 이런 단점을 보완하고자 비접촉식 센서의 개발이 활발히 진행 중이며, 특히 비전센서를 활용한 동적 변위 측정에 관한 연구 및 개발에 많은 진척이 있다. 비전센서를 활용한 동적 변위 측정 시스템은 내 적 파라미터 및 외적 환경조건에 따라 측정 정확도가 크게 변화한다. 주된 내적 파라미터로 영상장비 의 공간분해능은 이미지 센서의 물리적 크리와 촬영거리의 증가 혹은 관심영역이 작아짐에 따라 영향 을 많이 받는다. 외적 환경조건으로 저조도 환경에서 타겟의 밝기차이가 줄어들어 이미지 프로세싱 과 정에서 불리한 조건이며, 이는 동적 변위 측정 정확도 저하로 이어진다. 본 연구에서 저조도 환경에서 비전센서의 운용거리 한계를 초해상화를 적용하여 극복하고자 하며, 인공적 및 자연적 타겟에 대한 동 적 변위 측정 성능을 비교 분석하였다. 동적 변위 측정 실내 실험을 위해 저조도 조건에서 3층 전단 구조물을 9Hz로 가진하였다. 동시에 Sony사의 DSC-100M7 카메라를 활용하여 조화진동으로 인해 발생되는 각층의 변위를 FHD화질 120FPS로 촬영하였고 측정 정확도 비교 분석을 각층의 LVDT 측 정값으로 진행하였다. 촬영거리를 10m를 기준으로 10m씩 증가하면서 최대 40m까지 변위 값을 측정 하였으며, 공간분해능 증가를 위해 GAN기반 초해상화 모델인 RealSR을 적용시켰다. 초해상화를 활용 하여 동적변위를 측정한 결과 저조도 환경에서도 비전센서의 운용 거리가 증가함을 확인할 수 있었으 며, 동시에 변위 측정 정확도도 함께 상승하는 것을 보여줬다.

최근, 큰 처짐과 다수의 균열을 동반하는 유사연성 거동과 부식에 대한 높은 내구성의 특징을 가진 FRCM(Fabric-Reinforced Cemenetitious Matrix) 복합체에 대한 관심이 증가하고 있다. 철근콘크리트 부재에 대해 다양한 장점을 지닌 FRMC 복합체를 적용할 경우 전단내력의 증대를 예상할 수 있으며, 이를 통해 내진성능이 요 구되는 철근콘크리트 구조물에 효과를 기대할 수 있다. 본 연구에서는 FRCM 복합체가 보강된 철근콘크리트 기둥에 대해 정적 반복가력 실험을 수행하고, 그 거동을 평가 하였다. 철근콘크리트 기둥은 직사각형 형상으로 단면의 크기가 300 × 300 mm이고, 순 높이는 800 mm로 제작되었다. 정적 반복가력 실험은 설정한 가력패턴에 따라 변위제어를 통해 횡 하중을 가력하 였고, 초기 축력은 기둥 용량의 10 %로 적용하였다. 정적 반복가력 실험 결과, 무보강 실험체 대비 약 27.33 %의 증진된 강도를 나타내었으며, 최대 강도 발현 시 층간변위비가 무보강 실험체 대비 약 187.6% 높게 나타냄에 따라 FRCM 복합체가 적용된 철근콘크리트 기둥의 높은 연성 거동을 확인 할 수 있다. 다만, FRCM 복합체를 실제 구조물에 적용하기 위해서는 추가적인 설계인자 개발을 통해 안 정성 및 신뢰성을 확보하는 것이 필수적이라고 판단된다.

Evaluation of low temperature performance of asphalt mixture is significant not only for mitigating transverse thermal cracking but also for preventing potential traffic accidents. In addition, the engineers in pavement agency need to inform the proper pavement section where urgent management is needed. Since early 2000, Korea Expressway Corporation Research Division (KECRD) developed an 3D Pavement condition Monitoring profiler vehicle (3DPM) to survey expressway pavement surface condition precisely. The management of whole expressway network became more precise, effective and efficient than before due to application of 3DPM and HPMS. One thing recommended is: performing extensive mechanical test and corresponding data analysis work procedure to further strengthen the feasibility of current 3DPM approach and HPMS. In this paper two activities were considered: first, the pavement section where the urgent care is recommended is selected by means of 3DPM approach. Then asphalt mixture cores were acquired on that specified section then low temperature fracture test: Semi Circular Bending (SCB) test, was performed. The mechanical parameters, energy release rate and fracture toughness were computed then compared. It is concluded that the current 3DPM approach in KEC can successfully evaluate and analyze selected pavement condition. However, more extensive experimental works are needed to further strengthen the current pavement analyzing approaches.

이 연구는 한국어교육능력검정시험의 문법 영역 문항이 예비한국어 교 사가 갖추어야 할 문법 교육 역량을 평가하기에 타당한지를 비판적으로 고찰하고, 한국어교육능력검정시험 문법 영역 문항의 개선 방안을 구체 적으로 모색하는 것을 목적으로 한다. 연구 방법으로는 한국어교육능력 검정시험 제1회(2006년)-제18회(2023년)까지의 시험 문항에서 한국어 문 법 영역과 관련이 있는 한국어어휘・형태론, 한국어통사론, 한국어규범, 한국어문법교육론 과목 623개의 문항을 분석하였다. 분석 결과, 전체적 으로 이론적인 문법 지식을 묻는 문항으로 출제가 되는 경향이 많았다. 그렇지만 한국어 교사에게는 교실 현장에서 외국인 학생들에게 쉽고 재 미있게 가르칠 수 있는 ‘가르치기 위한 지식’이 중요하다. 그러므로 한국 어교육능력검정시험의 문법 영역에서도 예비한국어 교사들이 한국어 교 실 현장에서 실제적으로 접하게 될 교실 현장과 관련이 있는 문항으로 출제가 되어야 할 것이다. 이를 위해 본 연구가 예비한국어 교사의 한국 어 문법 교육 능력을 제대로 측정할 수 있는 한국어교육능력검정시험의 초석이 되기를 바란다.

In recent automobile development, vehicle weight reduction has become a very important goal. Seat weight reduction is a large portion of vehicle weight reduction. In this study, a specimen tensile tests were conducted on the Almag material, which is an alloy of aluminum and magnesium, and also conducted on SAFH440, SAFH 590, SAFC780, and SAFH980, which are mild steel materials used in the seat frame. The tensile specimen tests were carried out in two speed; 2mm/s and 4mm/s, and the obtained stress to strain curve was converted to the analysis material card of true stress to true strain curve to be used in the seat structural analysis. The constructed analysis material card was used in the specimen tensile finite element analysis, and the analysis result was able to obtain the stress to strain curve similar to the test result.

손 위생 제품이 다양화됨과 동시에 각 활용 방법에 따 라 그 효능을 평가하는 여러 시험 방법들이 보고되고 있 다. 하지만 평가 방법에 따라 각 제품의 항균 효능은 다 르게 나타나며, 이로 인해 제품의 실제적인 효능을 확인 하는 데에 어려움이 있을 수 있다. 손 위생 제품의 효능 평가방법 비교에 초점을 둔 연구는 매우 제한적이며, 특 히 돼지피부를 이용한 ex vivo에 대한 연구는 극히 드물 다. 이에 본 연구는 손 위생 제품 중 리브온 소독제와 워 시오프 세정제에 대해 각각의 항균 평가 방법을 종합적으 로 비교했고, ex vivo 시험에 영향을 미칠 수 있는 요인을 파악하여 연구 단계에서 효율적인 ex vivo 시험의 신뢰성 을 향상시키고자 하였다. in vitro 시험으로써 액체 현탁을 기반으로 하는 time-kill 시험을 진행했고, in vivo 시험은 최소 20명의 참여자를 대상으로 진행되었다. ex vivo 시험 은 규격화된 돼지 피부를 이용하여 in vivo 시험과 동일한 방법으로 진행하면서 소독제의 최적 처리량과 세정제 사 용 시 첨가되는 물의 양을 제안했다. 시험에 사용된 손 소 독제는 in vitro 시험에서 모두 5 log 이상의 세균 감소율 을 보인 반면, ex vivo와 in vivo에서는 훨씬 낮은 살균 활 성을 보였으며, 특히 알코올 함량이 낮은 손 소독제에서 는 1 log 미만의 살균 활성을 나타냈다. 반면에 손 세정 제의 in vitro 시험 결과, 대장균에 대해서는 1 log 이하의 낮은 항균력을 보였으나, ex vivo 와 in vivo 시험 결과에 서는 이보다 높은 항균력을 유사하게 나타냈다. 본 연구 에서는 ex vivo 와 in vivo 시험 방법이 리브온과 워시오 프 타입 제품의 두가지 다른 항균 메커니즘을 반영할 수 있음을 확인했다. 이로 인해 최적의 조건으로 설정된 ex vivo 시험은 빠르고 정확한 항균 평가법이 될 수 있음을 제시한다.

In the case of the Pohang earthquake, which had a magnitude of 5.4 in 2017, geotechnical damages such as liquefaction and ground settlement occurred. The need for countermeasures has emerged, and experimental research in the Pohang area has continued. This study collected undisturbed samples from damaged fine-grained soil areas where ground settlement occurred in Pohang. Cyclic tri-axial tests for identifying the dynamic characteristics of soils were performed on the undisturbed samples, and the results were analyzed to determine the cause of ground settlement. As a result of the study, it was determined that in the case of fine-grained soils, ground settlement occurred because the seismic load as an external force was relatively more significant than the shear resistance of the very soft fine-grained soils, rather than due to an increase in excess pore water pressure.

Understanding the behavior of soil under cyclic loading conditions is essential for assessing its response to seismic events and potential liquefaction. This study investigates the effect of non-plastic fines content (FC) on excess pore pressure generation in medium-density sand-silt mixtures subjected to strain-controlled cyclic direct simple shear (CDSS) tests. The investigation is conducted by analyzing excess pore pressure (EPP) ratios and the number of cycles to liquefaction (Ncyc-liq) under varying shear strain levels and FC values. The study uses Jumunjin sand and silica silt with FC values ranging from 0% to 40% and shear strain levels of 0.1%, 0.2%, 0.5%, and 1.0%. The findings indicate that the EPP ratio increases rapidly during loading cycles, with higher shear strain levels generating more EPP and requiring fewer cycles to reach liquefaction. At 1.0% and 0.5% shear strain levels, FC has a limited effect on Ncyc-liq. However, at a lower shear strain level of 0.2%, increasing FC from 0 to 10% reduces Ncyc-liq from 42 to 27, and as FC increases further, Ncyc-liq also increases. In summary, this study provides valuable insights into the behavior of soil under cyclic loading conditions. It highlights the significance of shear strain levels and FC values in excess pore pressure generation and liquefaction susceptibility.

In this study, the impact load resulting from collision with the fuel rods of surrogate spent nuclear fuel (SNF) assemblies was measured during a rolling test based on an analysis of the data from surrogate SNF-loaded sea transportation tests. Unfortunately, during the sea transportation tests, excessive rolling motion occurred on the ship during the test, causing the assemblies to slip and collide with the canister. Hence, we designed and conducted a separate test to simulate rolling in sea transportation to determine whether such impact loads can occur under normal conditions of SNF transport, with the test conditions for the fuel assembly to slide within the basket experimentally determined. Rolling tests were conducted while varying the rolling angle and frequency to determine the angles and frequencies at which the assemblies experienced slippage. The test results show that slippage of SNF assemblies can occur at angles of approximately 14° or greater because of rolling motion, which can generate impact loads. However, this result exceeds the conditions under which a vessel can depart for coastal navigation, thus deviating from the normal conditions required for SNF transport. Consequently, it is not necessary to consider such loads when evaluating the integrity of SNFs under normal transportation conditions.

In this research, a new Test and Evaluation (T&E) procedure for defense AI systems is proposed to fill the existing gap in established methodologies. This proposed concept incorporates a data-based performance evaluation, allowing for independent assessment of AI model efficacy. It then follows with an on-site T&E using the actual AI system. The performance evaluation approach adopts the project promotion framework from the defense acquisition system, outlining 10 steps for R&D projects and 9 steps for procurement projects. This procedure was crafted after examining AI system testing standards and guidelines from both domestic and international civilian sectors. The validity of each step in the procedure was confirmed using real-world data. This study's findings aim to offer insightful guidance in defense T&E, particularly in developing robust T&E procedures for defense AI systems.

This paper is a study of a prototype development project in progress as part of an industry-academia joint technology development task. The so-called bird collision test equipment is a study to prove the validity of the performance and function content of the test equipment through the speed measurement of the specimen corresponding to the bird and other test procedures to evaluate its function by developing the bird collision test equipment, and the research and development goal is to establish a bird collision simulation test environment and develop data performance methods through this industry-academia study.

Liquified hydrogen is considered a new energy resource to replace conventional fossil fuels due to environmental regulations by the IMO. When building tank for the storage and transportation of liquified hydrogen, materials need to withstand temperatures of -253°C, which is even lower than that of LNG (-163°C). Austenitic stainless steel mainly used to build liquified hydrogen tank. When building the tanks, both the base material and welding zone need to have excellent strength in cryogenic condition, however, manual arc welding has several issues due to prolonged exposure of the base material to high temperatures. Laser welding, which has some benefits like short period of exposure time and decrease of thermal affected zone, is used many industries. In this study, laser bead on plate welding was conducted to determine the laser butt welding conditions for STS 304 and STS 316L steels. After the BOP test, cross-section observations were conducted to measure and compare four bead parameters. These tendency result of laser BOP test can be used as conditions laser butt welding of STS 304 and STS 316L steel.

건축물에 가해지는 풍하중을 평가하는 방법은 과거로부터 많은 발전을 이루었다. 그 중 비교적 간단한 방법인 가스트하중계 수법이 있다. 정적풍하중에 동적계수를 곱하여 등가정적풍하중을 평가하는 방법으로 여러나라 기준에서 사용되고 있다. 동적계수는 가 스트영향계수(Gust Effect Factor:DGEF)와 가스트하중계수가(Gust Loading Factor:MGLF)가 사용된다. DGEF는 변위 기반으로서 이론 적인 가정을 통해 산출할 수 있는 반면 그 과정이 다소 복잡하고, MGLF는 모멘트를 기반으로 하며 풍동실험으로 전도모멘트를 측정 하여 산정할 수 있지만 기초자료를 구축하는 것에 많은 시간과 노력이 소요된다. 따라서 본 연구에서는 MGLF 산정 시 필요한 풍방향 평균풍력계수C F, 평균전도모멘트계수C M, 변동전도모멘트계수 C M 가 다양한 형상비( ), 변장비(D/B), 지표면조도구분(α)에 따 라 변화하는 경향을 비교 분석하였다. 이를 통해 풍방향 평균풍력계수 C F, 평균전도모멘트 관련 계수 C g, 변동전도모멘트 관련 계수 C g 의 경험식을 제안하여 MGLF 산정에 대한 기초자료를 제시하였다.

The study aim was to develop and test the effects of integrated simulation pertaining to patients with schizophrenia using a hypertensive crisis module for nursing students. Methods: This pilot study with seven undergraduate nursing students used a single group, pre-post test design. Integrated simulation pertaining to patients with schizophrenia using a hypertensive crisis module was developed based on the ADDIE model (i.e., Analysis, Design, Development, Implementation, and Evaluation), expert meetings with subject professors, a literature review, a preliminary survey, and focus group interviews. Data were collected and measured for general characteristics of the study participants, critical thinking disposition, problem-solving, clinical judgment, self-efficacy, simulation design, and simulation effectiveness. Qualitative contents were analyzed through focus group interviews. Results: No statistically significant differences were found in class design, critical thinking disposition, problem-solving, clinical judgment, and self-efficacy after applying the integrated simulation module. Based on the data obtained from the focus group interviews of study participants, the following four categories were established: “Integrating knowledge and applying it to practice,” “Nursing in unexpected situations,” “Challenged to be an expert,” and “Ensuring receptive and psychological safety in simulation practice.” Conclusion: An integrated simulation module was developed to integrate the nursing problems associated with individual subjects beyond the scope of one subject, and the effect was verified by applying it

PURPOSES : The purpose of this study is to investigate the tendency of material property estimation under different concrete distress conditions and curling conditions when non-destructive tests such as rebound hammer and surface deflection test are applied to concrete pavement. METHODS : Nondestructive tests using Schmidt hammer and Falling Weight Deflectometer were performed to inspect the expressway concrete pavements constructed more than 20 years ago. Some results were compared with core tested elastic modulus and compressive strength. RESULTS : As a result of the rebound test, the section with Alkali-Silica Reaction(ASR) distress was outside the range of the existing estimation formula, but the control section was found to be within the range of the existing estimation formula. As a result of the physical property estimation through deflection test, the section with ASR distress showed greater fluctuations in the estimated material properties and deflection ratio compared to the control section, showing that the ASR damage seems to affect the slab deflection behavior. CONCLUSIONS : The rebound test may not sufficiently reflect the decline in material properties due to concrete damage. The deflection test can obtain results that reflect the deterioration of material properties, but it was confirmed that significant variability may occur, so it seems to necessary to perform complementary indoor core tests with nondestructive testing(NDT) tests.

In this study, a prefabricated buckling brace (PF-BRB) was proposed, and a test specimen was manufactured based on the design formula for the initial shape and structural performance tests were performed. As a result of the experiment, all standard performance requirements presented by KDS 41 17 00 and MOE 2021 were satisfied before and after replacement of the reinforcement module, and no fracture of the joint module occurred. As a result of the incremental load test, the physical properties showed a significant difference in the stiffness ratio after yielding under the compressive load of the envelope according to the experimental results. It is judged necessary to further analyze the physical properties according to the experimental results through finite element analysis in the future.